The environment is everywhere.

Intersex in smallmouth and largemouth basses is widespread in numerous river basins throughout the United States is the major finding of the most comprehensive and large-scale evaluation of the condition, according to U.S. Geological Survey (USGS) research published online in Aquatic Toxicology.
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This condition is primarily revealed in male fish that have immature female egg cells in their testes, but occasionally female fish will have male characteristics as well.
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The percentage of intersex largemouth bass per site ranged from 8 to 91 percent and was most prevalent in the southeastern United States. The Pee Dee River at Bucksport, S.C., contained the highest percentage of intersex fish (91 percent),

Causation was not determined, but many point to endocrine disrupting chemicals in personal home products, drugs, and other sources, which end up in sewage and pass through sewage plants because these plants do not completely remove the compounds.